Heretofore, pile weatherstripping has been made in large quantities (thousands of feet of weatherstripping per anum) using a process initially developed by Robert Horton (see Horton, U.S. Pat. No. 4,148,953, issued Apr. 10, 1979) where the yarn is helically wound on a traveling band or mandrel, and a backing member of plastic material like the material of the yarn is ultrasonically welded to the yarn along an edge thereof while the yarn and the mandrel move together. The like materials of the yarn and the backing are polypropylene which forms a reactive weld when ultrasonic energy is applied thereto. The following patents also describe the fabrication of pile weatherstripping and also show methods and apparatus for incorporating air and water filtration barrier fins in or along the sides of the pile: Horton, U.S. Pat. No. 4,302,494, issued Nov. 24, 1981; Horton, U.S. Pat. No. 5,060,422, issued Oct. 29, 1991; Johnson et al., U.S. Pat. No. 5,338,382, issued Aug. 16, 1994; Johnson, U.S. Pat. No. 5,817,390, issued Oct. 6, 1998; and Johnson U.S. Pat. No. 5,807,451, issued Sep. 15, 1998. (The patents cited in this paragraph are referenced hereinafter as the “Horton and Johnson patents”).
It is especially desirable to use nylon for the pile of the weatherstripping because of its wear characteristics and of the ability to absorb crush force as may be applied on the weatherstripping by fenestration products (doors and windows) in which the weatherstripping is installed when such products are forcibly closed. A reactive bond capable of withstanding such forces is especially desirable. It is also desirable to utilize polypropylene in the backing inasmuch as polypropylene is a lower cost material than nylon and provides a competitive advantage in the marketing of the weatherstripping over weatherstripping made entirely of nylon.
It has been proposed to extrude the backing around the yarn thereby providing a mechanical connection there between, as opposed to a reactive or chemical bond. An extrusion attachment is described in U.S. Pat. No. 5,093,181 to Sanchez, issued Mar. 3, 1992. Interleaved filaments of nylon and polypropylene have also been proposed for providing the pile. Such mixed yarns are mechanically bonded when welded causing the polypropylene to melt and capture the nylon, especially where the polypropylene/nylon yarn is encapsulated in polypropylene to provide the backing for the yarn. Such piles of unlike plastics (Mylar and polypropylene) have been proposed in Ohara et al., U.S. Pat. No. 6,115,566, issued Sep. 5, 2000 and Pawson et al., U.S. Patent Application Publication No. 2009/0258184, published Oct. 15, 2009.